Wrigley went to work as a traveling soap salesman for his father’s company at age 13. In 1891 he went to Chicago as a soap distributor and there started offering baking powder as a premium with each box of soap. In 1892 he began selling baking powder as a sideline, offering chewing gum as a premium. The chewing gum proved more popular than the baking powder, so he dropped both soap and baking powder to sell only chewing gum. He also gave dealers premiums, such as clocks, coffee grinders, or fishing tackle, which varied with the size of the order.

Wrigley relied on advertising to boost sales of Wrigley’s Spearmint chewing gum, which he introduced in 1893. By 1908, sales of Wrigley’s Spearmint were more than $1,000,000 a year. In 1911 Wrigley took over Zeno Manufacturing, the company that made his chewing gum, and established the Wm. Wrigley Jr. Company. His company became one of the biggest advertisers in the United States. By 1925, when Wrigley turned the company presidency over to his son, Philip, and became chairman of the board, the Wrigley company had factories in the United States, Canada, and Australia.

Wrigley was the developer of Santa Catalina Island, off the coast of southern California. From 1921 until 1951 (except during the World War II years), a National League baseball club, the Chicago Cubs, a Wrigley family interest, spent its spring-training sessions on Catalina. Wrigley’s Chicago headquarters, the Wrigley Building, became a noted architectural landmark of that city.